Combined effects of pinning and adhesion force on solid\liquid interfacial friction behaviors under applied voltage

The interfacial friction between solid and liquid under applied voltage are vital to actuate droplets. In this paper, the pinning and adhesion force between solid and liquid were measured to study the interfacial friction behaviors under applied voltage. Results showed that the pinning force increased firstly and then decreased with increasing of surface roughness. Moreover, the adhesion forces for the surface with lower roughness were bigger than that for the surface with higher roughness. It suggested that the interfacial friction force was closely associated with the quantity of realigned interfacial water molecules under applied voltage. These findings will extend the understanding of solid/liquid interfacial friction mechanisms under applied voltage, and then to lower the actuation voltage of droplets.